<template>
  <div class="goods-image">
    <div
      class="large"
      v-show="show"
      :style="[{ backgroundImage: `url(${images[currIndex]})` }, LargeBgPosition]"
    ></div>
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt />
      <div class="layer" :style="LayerPotsion" v-show="show"></div>
    </div>
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex = i" :src="img" alt />
      </li>
    </ul>
  </div>
</template>
<script>
import { ref, watch, reactive } from 'vue'
import { useMouseInElement } from "@vueuse/core"
export default {
  name: 'GoodsImage',
  props: {
    images: {
      type: Array,
      default: () => []
    }
  },
  setup(props) {
    const currIndex = ref(0)

    const { show, target, LargeBgPosition, LayerPotsion } = usePreviewImg()


    return {
      currIndex,
      target, show, LargeBgPosition, LayerPotsion
    }
  }

}
const usePreviewImg = () => {
  const target = ref(null)
  const show = ref(false)
  const { elementX, elementY, isOutside } = useMouseInElement(target)
  const LayerPotsion = reactive({ left: 0, top: 0 })
  const LargeBgPosition = reactive({ backgroundPositionX: 0, backgroundPositionY: 0 })
  watch([elementX, elementY, isOutside], () => {

    // 设置是否显示预览大图
    show.value = !isOutside.value
    if (show.value) {
      // 控制X轴方向的定位 0-200 之间
      if (elementX.value < 100) LayerPotsion.left = 0
      else if (elementX.value > 300) LayerPotsion.left = 200
      else LayerPotsion.left = elementX.value - 100
      // 控制Y轴方向的定位 0-200 之间
      if (elementY.value < 100) LayerPotsion.top = 0
      else if (elementY.value > 300) LayerPotsion.top = 200
      else LayerPotsion.top = elementY.value - 100
      // 设置大背景的定位
      LargeBgPosition.backgroundPositionX = (-LayerPotsion.left * 2) + 'px'
      LargeBgPosition.backgroundPositionY = (-LayerPotsion.top * 2) + 'px'
      // 设置遮罩容器的定位
      LayerPotsion.left = LayerPotsion.left + 'px'
      LayerPotsion.top = LayerPotsion.top + 'px'
    }
  })

  return { target, show, LayerPotsion, LargeBgPosition }

}
</script>


<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;
  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat; //画面原始尺寸大
    background-size: 800px 800px;
    background-color: #f8f8f8;
    // background-position-y: -100px; // 移动背景图片来控制展示区
  }
  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move; // 控制鼠标样式
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, 0.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>